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Poster: Round Robin Date: Aug 28, 2009 10:10am
Forum: GratefulDead Subject: Differentiate betwteen a mp3 at 320 and a flac?

Maybe my ears are shot, but can you hear a difference?

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Poster: dead-head_Monte Date: Aug 28, 2009 3:58pm
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

I believe the difference is found in the overtones. The subtle losses will be noticeable in the overall ambience, "they [pros] say." This is my understanding. I can't hear it. I have no special ear-training either, even tho I was a soundman for 3 bands 35 years ago. Since then I've worked in 6 TV stations, 3 cable-TV networks, and many high-end a/v production centers. I have very good hearing. I am not trained in listening and knowing exactly what perfect symphonic sounds "are".

People who know exactly how the best sounding Martin guitars in the world sound, and the best sounding Stradivarius violins sound, can tell you much better than I about the harmonics produced by these instruments.

D-100%20Deluxe_f.jpgwhite-dot-2x2.gif180px-Stradivarius_violin_front.jpg

When I encode to mp3, I have 3 great s/w to choose from. Trader's Little Helper is what I use for everything except encoding to mp3. I have Samplitude v 7.x. I use it for all my editing, signal processing, and remastering. I also have CD-Tag. It's a great utility just like TLH. I use CD-Tag for encoding lossless audio to mp3, because it uses the LAME mp3 encoder for V-B-R. Thanks to the dedicated work of its developers and the open source licensing model that allowed the project to tap into engineering resources from all around the world. Best way to go for mp3. I have a great ear for "good sound." I cannot tell the difference bet vbr mp3 and flac, let alone 320 kb mp3.

The theory behind this could be to consider what an ideal signal - audio, video, microwave - or any other spectrum is. If I put a perfect square wave into a circuit, processor, or device, I want a perfect square wave output from the device. In simple terms, a square wave can be created by generating a single fundamental audio frequency and an infinite number of harmonics.

Synthesis_square.gif

For the rest of us, we can measure the performance of any "process" using test equipment in the lab. Passing this signal perfectly through a "device" is always the toughest test. On the other hand, I doubt square waves exist in nature. Here's the math.

c8fd420449212dab93fa7444f0a90fa2.png



This post was modified by dead-head_Monte on 2009-08-28 22:58:06

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Poster: Earl B. Powell Date: Aug 28, 2009 8:27pm
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

The basic notion of MP3 is to reduce the size of files and it does so by compression of frequencies across the spectrum. Someone mentioned the cymbal test, which is fairly valid, except what gets compressed in that case is not the attack but the decay...or length of reverberation.

Ultimately this compression, depending on how many bytes are remaining, really removes the more "ambient" nature of the music rather than what I would describe as "physical."

IMO that the quality of the playback equipment has as much to do with it as the ear. I just traded out a 30 year old AIWA 50 watt mini amp for an even older Marantz quad receiver and the difference was like night and day. The frequency range may not be wider, but it was certainly altered by this change. Just like East Coast versus West Coast loudspeaker design.

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Poster: dead-head_Monte Date: Aug 29, 2009 10:42am
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

This is a tough subject to explain, imo. It's very challenging to discuss, let alone "hear" the losses. Listeners trying to "hear" and compare some of these differences - between any 2 sources - might consider:

1) Earl is correct. Most important - you will need a very good audio playback system - perhaps high-end headphones - in order to attempt hearing this stuff.

2) You will need some very good audio sources (or even test signals) to try test-encoding to mp3 using different encoding methods. It is important to first become extremely familiar with exactly what this material sounds like before you experiment.

3) It will probably help if you have a quick-acting A-B switch to compare any 2 sources - for judging the fidelity, or losses between them.

Here's 3 semi-technical points I copied-pasted from Wikipedia that may explain the "cymbal test":

Some audio is hard to compress because of its randomness and sharp attacks. When this type of audio is compressed, artifacts such as ringing or pre-echo are usually heard. A sample of applause compressed with a relatively low bit rate provides a good example of compression artifacts.

Besides the bit rate of an encoded piece of audio, the quality of MP3 files also depends on the quality of the encoder itself, and the difficulty of the signal being encoded. As the MP3 standard allows quite a bit of freedom with encoding algorithms, different encoders may feature quite different quality, even with identical bit rates. As an example, in a public listening test featuring two different MP3 encoders at about 128 kbit/s, one scored 3.66 on a 1–5 scale, while the other scored only 2.22.

VBRs (variable bit rate) - Some audio parts will be much easier to compress, such as silence or music containing only a few instruments, while others will be more difficult to compress. So, the overall quality of the file may be increased by using a lower bit rate for the less complex passages and a higher one for the more complex parts. With some encoders, it is possible to specify a given quality, and the encoder will vary the bit rate accordingly. Users who know a particular "quality setting" that is transparent to their ears can use this value when encoding all of their music, and not need to worry about performing personal listening tests on each piece of music to determine the correct bit rate.

What's the point with all this? 1) Large lossless audio Music Libraries take up lots of Disk Drive space, and so does their backups. 2) Trading, sharing, and transferring these files over the internet takes up lots of bandwidth. 3) Portable mp3 players have limited storage.

If you are a Dead-Head --- then I recomment that you listen to, collect and trade all your shows only using Lossless Audio. Please, please - never take a MP3 and decode it to Wav, and share or trade it as "lossless". It is not lossless. It pollutes the music files and this pisses people off. Use vbr mp3 encoding when you put your music on your i-Pod. It sounds pretty damn good. Some mp3 players may not support vbr. VBR p/b feature was the only reason I bought an i-Pod a couple of years ago. The 24-hour battery life was also a great feature for me. It was very good for camping and light-weight backpacking trips.

People who are creating, producing, and recording tons of their own "new" music are perhaps facing the biggest challenge: how in hell can they cut down on some of those HUGE file sizes? This may be the most critical MP3 issue for pro-sumers to consider.

This post was modified by dead-head_Monte on 2009-08-29 17:42:44

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Poster: Earl B. Powell Date: Aug 29, 2009 12:43pm
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

Word. In the very least we are light years ahead of where we were ten years ago, dealing with analog and all the foibles of tape speed as well as the great spectrum of playback equipment quality.

Really the biggest thing I can distinguish between some lossy and all lossless recordings can be described as ambiance. It's the same thing that audiophiles said about the difference between analog LP's or tapes and the "cold" sound of digital. I always thought they overplayed it, as I found it very hard to distinguish the difference between a CD and an LP played on good Hi-Fi equipment.

The widest variation in ambiance we deal with regarding the archived recordings here and at BT sites is reverb. Reverb is either naturally occurring in a room or a hall, or processed by use of various kinds of equipment.

One of the most common complaints about SBD recording is their "sterile" nature. That sterility is the utter lack of reverb in the sound process. The signal is passed from the microphone, through the board and onto the tape machine. Since reverb or echo is naturally occurring in a hall or arena, it's rarely required as a part of signal processing to enhance the sound. (It's counterpart is in the studio, where there is typically no echo, and reverb is added in post production to keep the sound from being so dry or sterile.)

Some boards sound more natural than others simply because of ambient "bleed" into the microphones. This is where the hall reverb is picked up along with the accumulation of desired signals and makes it to the recording device. More sterile or dry sounding boards either come from halls that lack this natural echo or the microphone levels have been set fairly low and do not pick up the bleed from the room.

This is one of the reasons that the matrix recordings have gained such popularity. By combining the AUD, which typically will have picked up nearly 100% of the reverberations in the arena and the dry signal of the SBD, you come up with a very natural sounding recording. Most of these blends have been 60-40 or 65-35 SBD to AUD, and I think that's because there is the notion to have some crowd noise for purposes of a historic archival event. IMO that depending on the venue that an 80-20 would allow the SBD recording to be "wet" enough to take away that aura of sterility.

So reverb is the one critical element that's minimized as an "ambient" characteristic when decoding to lossy formats, but it's also an element of "ambiance" with the recordings we deal with even in lossless formats.

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Poster: hippie64 Date: Aug 29, 2009 1:42pm
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

Yah Man I can dig it . Ambiance was w/ the LP because that reverb and other back ground noise permiated the album, That was the problem I think I had at first w/ digital I don't think my ears were used to hearing the note so perfectly reproduced. just my 2 cents worth and with inflation well I wont go there this is a music forum.

Peace

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Poster: hippie64 Date: Aug 29, 2009 11:47am
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

I agree totally DH Monte besides If the music was produced for that signal (Mp3) then take a hammer and smash it as small as u want put it in an iphone or mp3 player and carry it to the monn if you want just don't expect that the music will sound as it was produced . I'm no scientist (or scientoligist) but I know because I can hear the differene. Sometimes not in a single note but in a chord or drum track, that sparkle is definetlly missing.
I'm guilty of replaceing a music file into my libary in mp3 it saves space but I dont treat it the same as my recordings that have their musical integrity. I've dl'ed mp3 shows from the net even shows called soundboards but I'm not niave enough to think that was the way the Dead archived their music. I can't speak about rec'ing a show in mp3 and having a realistic facsmile of what was produced, If I was to lay a wager I'd place agianst the mp3 (am I a Loser).
My mp3's are treated as an audio reference for that paticular show. But if I want to count my ACTUAL shows that of course would only be Lossless.
I'm probably speaking arse but we believe what we believe

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Poster: Tidewater four ten O nine Date: Aug 29, 2009 4:58am
Forum: GratefulDead Subject: Re: Differentiate betwteen a mp3 at 320 and a flac?

Earl, you star!

That ("Someone mentioned the cymbal test, which is fairly valid, except what gets compressed in that case is not the attack but the decay...or length of reverberation".) I can understand.

Normally, with the mp3 the cymbal comes over as more of an abbreviated 'clang' - with the 'wav' it's more of a 'shimmer' i.e. it reverberates longer.

Either way, that (Bertha re-mix) of the September 1975 Lindley Meadows show comes over as a major eye- (err, ear-) opener in terms of cymbals - more cymbals than you can shake a stick at - and I've listened to a lot of Dead shows via here and (cough, cough) LLL's.

Cheers,

TW